MLA

Hughes, Langston, 1902-1967. Conference of African Writers of English Expression: material for discussion. Box 483, folder 12220. 1962 Jun. https://collections.library.yale.edu/catalog/17034185.

APA, 6th edition

Hughes, Langston, 1902-1967. (["Box 483, folder 12220"])(1962 Jun)[Conference of African Writers of English Expression: material for discussion]. https://collections.library.yale.edu/catalog/17034185.